Bacterial contamination of industrial applications (e.g., drilling fluids such as fracturing fluids or in water injection systems) is a source of problems. For example, microorganisms in oilfields, in injection water or industrial applications where water is collected from ponds or similar water sources may include iron-oxidizing bacteria, sulfate-reducing bacteria, slime-forming bacteria, sulfide oxidizing bacteria, yeast and molds, and protozoa.
Some industrially utilized fluids contain natural or synthetic polymers in their formulation that provide a food source for bacterial populations. Bacterial growth can result in souring of the crude oil in a reservoir, which is caused by the reduction of inorganic sulfate compounds to sulfides by certain bacteria. Bacterial metabolism can generate deleterious products, for example, hydrogen sulfide that aside from being a toxic gas can lead to decomposition of mud polymers, formation of problematic solids, such as iron sulfide, and/or corrosive action on drilling tubes and drilling hardware.
U.S. Pat. No. 3,240,737 discusses degradation of polyacrylamide and other water soluble polymers using ferrous salts and a ferric ion chelating agent in an oxygenated system. U.S. Pat. No. 6,884,884 to Magallanes et al. discusses the depolymerization of polymers and in particular, polysaccharides.